2012-10-09Exercise Zemax 7:Advanced Handling6Correction I6.1Schmidt telescopeSetup a system with a focussing spherical mirror with focal length f =25 mm,an incoming beam withdiameter D=20 mm at the wavelength=632.8 nm.a)The system is far from beeing diffraction limited.In the so called Schmidt telecope,an aspherical plate islocated in front of the mirror to correct the spherical aberration.Optimize a Schmidt corrector,if it is a platemade of N-BK7,has a thickness of 2 mm and is located in the focal plane of the mirror.Only the 4th orderof asphericity is allowed.Is the system now diffraction limitedb)Determine the maximum field angle of the system,which guarantees a diffraction limited behavior.Thepupil should be assumed to be at the corrector plate.c)Determine the spectral range,for which the system is diffraction limited on axis.d)If now for the nominal wavelength the mirror and the corrector plate are allowed to be aspherical.what isthe largest achievable field angle for a diffraction limited behavior6.2Retrofocus lensA system which consists of a negative and a stronger positive lens acts as a retrofocus lens,where thefocal length is shorter than the free working distance.a)Setup a retrofocus lens out of ideal lenses for a wavelength of 546.07 nm an incoming collimated beamdiameter of 10 mm with a negative lens of f=-50 mm.The positive lens should be determined in a way,that the free working diameter is twice the focal length and the numerical aperture in the image space is NA=02.b)To realize the system,now single lenses of finite thickness are inserted.Optimize the shape of thelenses for the monochromatic radiation on axis,if a heavy flint glass is used.What is the dominantdegradation effect for the qualityc)If the correction is considered,the positive lens is much more critical than the negative lens,because theray height is larger and the ray bending angle stronger.Therefore this lens shoud be splitted into two lensesand the bending of the negative lens is allowed to be changed too.Optimize the corresponding system.d)It is seen,that the performance is not diffraction limited.Therefore try to find better glasses in thecorrection.What is the best achievable Strehl ratio6.3ApochromateAn apochromatic lens shows a common image location for at least three wavelengths.If glasses on thenormal line are used,the curvature in an apochromatic lens becomes rather critical.Therefore to get arelaxed system,at least one glass far off from the normal line should be chosen.a)Establish a component with three cemented glass lenses with the materials BK7,SSK8 and F2.For thewavelengths e,F,C'the system should be apochromatic and have a focal length of f=100 mm with asmall numerical aperture of NA =0.02 in the image space.b)If now the spherical aberration should be corrected too,show,that the apochromatic condition can notlonger be fulfilled.c)To solve this problem,glasses with anormal partial dispersion must be used.If BK7 is substituted byPK50 and SSK8 by KZFS4,try the optimization again and enlarge the numerical aperture until thediffraction limited correction of the system is reached